The present invention is directed to a brake bleeding device, particularly to a device of simple construction that can be manufactured at reasonable cost, can be installed or removed from a vehicle within a fraction of a second, can bleed one or more brake cylinders at the same time and produce a full brake pedal without the mechanic stepping out of the car.
The introduction of hydraulic brakes has generated a need for a tool that will enable an individual to bleed the brakes on a automobile, truck, light airplane, and other hydraulic systems, effectively and quickly without help from a second party. The need for this tool is exemplified by the number of patents on brake bleeding devices.
The use of a biased check valve allows a massive amount of brake fluid to be expelled from the system, yet gives no indication to the person working the brake pedal as to when the job is completed.
The master cylinder is a very efficient pump and does not create a negative pressure when the brake pedal is released, but rather a zero pressure, therefore there is no need for a ball or needle check valve to prevent the back-flow of air or fluid.
The U.S. Patent and Trademark office has issued many patents on brake bleeding tools. These tools range from pressure vessels to vacuum pumps, one way valves replacing the factory bleeder valves and one way valves attached to the factory bleeder valves. Various means are employed to attach these tools to the brake cylinders, all these tools are basically one way check valves, all require monitoring as to when all air has left the system, none tell the mechanic when the job is done, none guarantee results.
The present invention is intended to meet all the requirements necessary to successfully bleed the brake of any vehicle or light aircraft.
Thus for example, U.S. Pat. No. 4,804,017 to Knapp, (1989) Titled Brake bleeder valve apparatus having integral check valve and method for bleeding brakes. Describes a replacement bleeder valve, that through a complex system has achieved a biased ball check valve. The claim that this tool will bleed all four wheel cylinders at the same time is in doubt since there is no way to stop the flow of brake fluid to any of the wheel cylinders, other than going under the vehicle and operating each of them independently. The brake fluid will take the path of least resistance and exit only one cylinder.
U.S. Pat. No. 4,149,560 to Berg (1979) Titled Brake bleeder valve, shows a resilient outer case, the upstream end is molded in a way enabling the tool to be clipped onto the factory bleeder valve, this tool contains a metal cylinder, the upstream end having a valve seat and a biased needle valve to control the flow of brake fluid, this tool does exactly the same thing as the Knapp tool..
U.S. Pat. No. 4,479,511 To Holland (1984) Titled One man brake check valve and coupler assembly. Shows a xe2x80x9cUxe2x80x9d shaped collar machined into a threaded bushing that is placed behind the frustum of the factory bleeder valve, a check valve assembly is screwed into it seating the valve assembly securely against the frustum of the factory bleeder valve, this requires the use of two wrenches in awkward places, yet does exactly the same thing as Knapp and Berg.
U.S. Pat. No. 4,989,639 To Sulwar (1991) Titled Brake bleeder check valve, Shows a standard brake bleeder valve with a built in check valve, it replaces the factory bleeder valve and has no advantage over Knapp, Berg, or Holland.
U.S. Pat. No. 4,865,171 To Miller (1989) Titled Brake bleeder valve, shows a rubber or plastic duck bill valve, which slips over the end of the factory bleeder valve, has no moving parts, and does exactly the same thing as Knapp, Berg, Holland or Sulwar.
Thus, although there is considerable prior art relating to brake bleeding tools, none are considered more relevant to the present invention than the art discussed above.
In accordance with the present invention a brake bleeding tool consists of a handle, a tubular extension designed to engage the factory bleeder valve of a hydraulic braking system, to be able to discriminate between air and brake fluid allowing the mechanic to know when the air is gone and when necessary discharge an amount of brake fluid under pressure, thereby duplicating the two man brake bleeding system.
A principal object of the present invention is to provide a positive means whereby one person can effectively bleed the brakes of a vehicle or aircraft.
A related object of this invention is to have the tool instantly engage or disengage the factory bleeder valve of the braking system.
Another object of this invention is to have a means to inform the mechanic when their is no more air in the braking system. According to yet another aspect of this invention to provide a means to open and close the brake bleeder valve.
According yet to another aspect of this invention a means to adjust the bias on the discriminator pin.
According yet to another aspect of this invention to provide a means to direct excess brake fluid into a container.
These and other related objects are realized by providing in a preferred embodiment of this invention a truly professional brake bleeding device.